Sequential jet shaped charge systems comprise a series of explosively driven, hollow metal cones which collapse under the force of a detonating explosive to form metallic jets capable of great penetrating power. In the sequential jet system, the first formed jet drills its hole, the second jet enters the same hole and deepens it, and so on. In this way a very deep hole may be formed by a small diameter system. A hole of similar depth, made by a single cone system, would require the use of a much larger diameter cone. In many instances a large diameter single-cone system is virtually impossible of achievement. For example, a gun-fired projectile is diameter limited; if the projectile incorporates a shaped charge to penetrate armor, the diameter of the shaped charge is also limited. With the use of sequential jets, however, penetration can be increased.
In designing sequential jet shaped charge devices it has been found that timing is very important to assure that no interaction occurs between jets in flight. This timing is all important because interaction or interference greatly degradates performance. Prior sequential jet shaped charge systems have been largely unworkable because they lacked the necessary timing capability.